From Bradley Anderegg, "Ok, I am re-submitting this with the changes we discussed. That is, there is a default implementation of osgDB::Archive::getDirectoryContents() that uses getFileNames(), and the osgDB::ArchiveExtended header was removed as it is now unnecessary.

Here is a quick list of the modified files:

Archive - getDirectoryContents() no longer pure virtual
Archive.cpp - default getDirectoryContents() implementation
unzip.cpp - modified to fix a bug where the same file will not load twice in a row
ZipArchive.h / ZipArchive.cpp - extends osgDB::Archive and provides support for random access loading within a .zip file
ReaderWriterZip.cpp - modified to use the ZipArchive class"

src/osgDB/Archive.cpp

@@ -50,3 +50,73 @@ Archive::~Archive()
     OSG_INFO<<"Archive::~Archive() closed"<<std::endl;
 }
 
+void cleanupFileString(std::string& strFileOrDir)
+{
+   if (strFileOrDir.empty())
+   {
+      return;
+   }
+
+   // convert all separators to unix-style for conformity
+   for (unsigned int i = 0; i < strFileOrDir.length(); ++i)
+   {
+      if (strFileOrDir[i] == '\\')
+      {
+         strFileOrDir[i] = '/';
+      }
+   }
+
+   // get rid of trailing separators
+   if (strFileOrDir[strFileOrDir.length()-1] == '/')
+   {
+      strFileOrDir = strFileOrDir.substr(0, strFileOrDir.length()-1);
+   }
+
+   //add a beginning separator
+   if(strFileOrDir[0] != '/') 
+   {
+      strFileOrDir.insert(0, "/");
+   }
+}
+
+osgDB::DirectoryContents osgDB::Archive::getDirectoryContents(const std::string& dirName) const
+{
+   DirectoryContents filenames;
+   getFileNames(filenames);
+
+   std::string searchPath = dirName;
+   cleanupFileString(searchPath);
+
+   osgDB::DirectoryContents dirContents;
+
+   DirectoryContents::const_iterator iter = filenames.begin();
+   DirectoryContents::const_iterator iterEnd = filenames.end();
+
+   for(; iter != iterEnd; ++iter)
+   {
+      std::string currentFile = *iter;
+
+      cleanupFileString(currentFile);
+
+      if(currentFile.size() > searchPath.size())
+      {
+         size_t endSubElement = currentFile.find(searchPath);
+
+         //we match the whole string in the beginning of the path
+         if(endSubElement == 0)
+         {
+            std::string remainingFile = currentFile.substr(searchPath.size() + 1, std::string::npos);
+            size_t endFileToken = remainingFile.find_first_of('/');
+
+            if(endFileToken == std::string::npos)
+            {
+               dirContents.push_back(remainingFile);
+            }
+         }
+      }
+   }
+
+   return dirContents;
+
+
+}